Cod sursa(job #2064462)

Utilizator vladcoroian2001Vlad Coroian vladcoroian2001 Data 12 noiembrie 2017 13:27:22
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.13 kb
#include <fstream>
#include <iostream>
#include <vector>
#include <set>

using namespace std;
ifstream fi("dijkstra.in");
ofstream fo("dijkstra.out");
const int nmax=50005,INF=1e9;
int n,m,x,y,c,BEST[nmax];
vector <pair <int,int> > V[nmax];
set <pair <int,int> > S;
void dijkstra()
{
    while(!S.empty())
    {
        auto nod=S.begin();
        S.erase(nod);

        int x = nod->second;
        //int current_cost = nod->first;

        for(auto edge:V[x])
        {
            int y = edge.first;
            int cost = edge.second;
            int new_cost = BEST[x] + cost;
            if(BEST[y]>new_cost)
            {
                S.erase(make_pair(BEST[y],y));
                BEST[y]=new_cost;
                S.insert(make_pair(BEST[y],y));
            }
        }
    }
}
int main()
{
    fi>>n>>m;
    for(int i=1;i<=m;i++)
    {
        fi>>x>>y>>c;
        V[x].push_back(make_pair(y,c));
    }
    for(int i=2;i<=n;i++)
        BEST[i]=INF;
    S.insert({0,1});
    dijkstra();

    for(int i=2;i<=n;i++)
    {
        if(BEST[i]==INF)
            BEST[i]=0;
        fo<<BEST[i]<<" ";
    }
    fi.close();
    fo.close();
    return 0;
}